Harvey l



H. L. HARRIS.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION men NOV. 15. m1.

1 324,739. Patented Dec. 9, 1919.

,fqljefL-f/a r16 ,BY A. fir x UNITED STATES PATENT orrio.

HARVEY L. HARRIS, OF ROCHESTER, NEW YORK, ASSIG-NOR TO THE STROMBERG- CARLSON TELEPHONE MANUFACTURING COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

TELEPHONE-EX Application filed November To all 'whom it may concern Be it known that I, HARVEY L. HARRIS, a citizen of the United States, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Telephone- Exchange Systems; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the invention.

My invention relates to telephone systems,

and more particularly to systems in which provide improved means to indicate to operators who answer a call the fact that it has already been answered, when that is the fact. I aim to indicate this in a suitable and adequate manner, and to combine this feature with other desirable features, in such a uirin the actuation of an movable a arat-us in the subsequent answering operators cord circuit. I accomplish this by having the cord circuit of the first answering operator apply a tone signal to the local opcrating strand of the line circuit of the calling subscriber in such a way, that anysubsequent answering operator will hear the tone in her telephone receiver without requiring the actuation of'such a subsequent answering operators supervisory relay.

' Other objects of my invention and the in vention itself will probably be better understood from a description of an embodiment of my invention, reference being made to the attached drawings in which I show a calling telephone at A connected on a line L leading to a central exchange and terminating thereat in multiple jacks J and J Associated with these multiple jacks are signal lamps S and S each connected in multiple, and each adapted to be operated when the telephone at A is operatively connected Specification of Letters Patent.

CHANGE "SYSTEM.

Patented Dec. 9, 1919.

15, 1917. Serial No. 202,122. r

operators telephone apparatus as at 0 for cuit O is illustrated in the drawing, it being understood that the balance of this operat-ors circuit is the same as that of the operators circuit shown at O The cord circuit C terminates in an answering plug P adapted to cooperate with the multiple jack J of the calling line to establish a connection therewith. 1 Likewise the answering plug P of the cord cir-' cuit D is adapted to cooperate with the multiple jack J of the calling line to establish a connection therewith.

A relay K is shown in each of the cord circuits adapted when operated to connect the respective operators telephone sets to the particular cord circuit. This relay is automatically operated whenever a call is answered; Like relays F and F are also shown as associated with the cord circuits C and D respectively. The functions of these relays will be later apparent from the description of the invention which follows.

The third strand controlling relayslll are shown at the calling ends of the cord circuits, and adapted to operate whenever a calling plug, such as P and P of the cord circuits is inserted in a jack, such as J 3 or J,

of a called line.

Perhaps my system and its functionswill be better understood from a description of the operation of the same'as follows Assume that the subscriber A makes a call by removing his receiver from the hook and closing the contacts of his hookswitch 0, a

circuit will be completed in the usual man ner for. the'line relay A which will operate closing its contacts which are in a circuit including a source of. current M, and the signal lamps S and S This signal will thereupon be lighted indicatingto the operat-he cord circuit C, and 0 for the cord circuit D. Only a portion of the operators cirtor whose set shown at i) and to the operator a portion of Whose so is shown at O alike,v that a call exists on the line L Each ope 'ator endeavoring to answer this call will insert the answering plug of their respective cord circuits into one of the multiple jacks rl or J adjacent to their positions.

One of the operators will make the connection of the plug and jack switch before the other. The one first to make 4 the conneo tion will ha 'e her operatofs so operatirely connected to the telephone line, and the other operator will not hate he operators set connected to the line. The ti will hen go ahead and converse, subscriber learn the number of the telephone, and complete the connection by inserting the calling plug oi? her cord circuit into the called line jack. Assuming that the operator u'hose set is shorrn at O is the connected operator, hat is, the one who first made the plug and ack 'tirh connection to the line, the operation o't tl e apparatus in her cord circuit involved 18; br etly 'lol- 7 su'itcn conline circuit will be operated over a c;;cu1 leading from the ground pole or battery, the oo iperatin winding of the cut-ofi relay, the contact of the plug and jack switch, circuit conduct r 2, the high resistance rinding R oil the induction coil 1, the opcarting uniding of the relay F the circuit conductor 3, leading to the negative vole of the sour so of conditions. The relay l? operating will 1 close its contacts at, shunting the iosiiltance winding 3 of the induction coil 1, and reduc ing thereby the resistance of the circu it lcadi11 our the conductor 2 to the source of current M, which includes the \Yifldilig' of the relay F The contacts 5 of the relay F in the circuit oi the source of tone current T SllO 'n at the bottom of the drawing will nor: be closed, the contzuts G of the relay F will also be closed completing a circuit includinq the source of current M, the winding 01"? th opcrators listening relay really made contacts 7 of the relay to o crate the relay K which when operated it connect the operators telephone by its conductors S and 9 to the talking strands of the cord circuit which are the time connected to the telephone line by the plugand i 4 R u jack switch; the connection being made through contacts 12 and 13 ot' the listening relay K. The normally made cont-acts 14L of the relay will now no broken to a purpose later to. be described Ne assuming that the operator later n sting the cord circuit D to the line by oit the plug and jack switch P J at s to 2 nsuer the call oi the subscriber Llllcll is being answered by the operator ose s t is shown at Such an attempt l he unsucc ;tul because the. relay F 1 not be operative tor the reason that the rrsntince of its operating circuit, including 41 resistance orits operating Winding ince oil the Winding Rot 1 action coil l which is in circuit with the w nding is of consi(lei-ably more reistauce than the \vinding of the relay F "ith u'l adjustment of the relay F beit will not with the amount of i I through its inding attract ari'naturc and will remain inoperative. heretore, the second operator attempting the call will not have her set conconrcrsational circuit with the in order to operate the listenin relay K of the cord circuit.

Prior to my invention. systems have been devised to accomplish this tailure to con- :uect the second operator's set to a *alling line under ti o above (1011i I am aware also that a system has vised "whereby apparatus iurolring' 'iug contacts of a siupcrrisory relay in the second connected operamrs cord circuit app icd an audible no to the opcratoi"s set to FPlflSj her that her attempt o answer tl call was unsuccessful, because of the more rapid answering ol' the call by another operator.

In my present invention 1 li ceuise aim to apply an audible ie. to the unsuccessful op raters telephone set but i do not depend upon the supervis ry rcla of the second connected cord c rcuit to operate since this it maylail to do when connected toliucs oi high 1CSlS"dll.'(3; due to the shunting effect of the first connected cord circuit supervisory relay. 1 therefore, as will be now shown, cause the audible tone to be applied by the actuation of apparatus in the successful or first connected cord circuit. the same being applied to a local operating strand of the line extended between the various operators positions and extended to the second connected opcrators tl@}')ll01lfi set by means of the plug and jarl; switch of the second connected V cord circuit.

In describing the ope F of the cord circuit C which is being de scribed as the first connected cord circuit, I describe contacts in the source of tone cur- 'ich it is nou placed in multiple cir- 'ou oi the relay rcntT as being closed. This tone circuit is L only operatively completed :to perform its functions a when "the second rconnected cord circuit is connected to-the line by;. means of its plug andajack switch asithe plug and, jack switch P J in which case thecom ypleted circuit involving this tone circuit :1 is as follows-:From the negative pole ofthesaid source of current, through intermittent 1 contacts of the interrupteifN, and the pri- Vnmary Winding of the transformer.- T:tothe of battery, thesecondary winding of the transformer T, the-contacts 5 of therelay F the'norma'l contacts 15- of therelay E, cir-V 'Cllll? conductor 17,1the toneawin'd'ing guof the relay F and trom thence returned to,

a ground.

The flow of current over 'thisacircuit will in turn induce a rapidly fluctuating flow: of

current in the operating winding" f oft-he relay F t-hetwo windings of tl1GSFtTClTGlfly -having an inductive eii'ect, one of the other,

and the tone current istherefore-created in theWvindmg if, :and complete circuit thereforeiis tracedas follows :From the negative pole ofthe source of'curren't M, circuit 1 conductor 3, the winding f of the relay F wthewnow closed contacts 4 thereof, c1rcu1t conductor 2, cooperating contacts of: the plug and jack'switch P yJ in'tercnultiplejack conductor 16, cooperating contacts of the plug and jack switch'P J circuit conductor 22in the cord circuit D; the winding R :of theinduction coil 1 the winding 7 of-the rela .F., circuit conductor 18- leadin back to the negative' pole of thesourceof current M. This circuit being completed fluctuating tone current will flow overthecsa meirand.

through theincluded winning 1R ofithe induction coil 1 inducing a like tone current-V in the secondary winding thereof vR This induced tone current flows in a'circuit traced from the groundpole of battery, the winding' R normal contacts 19 of the relay K,

ircuit conductor 20 common to aplurality of cord circuits and leading to the operators set 0 where it is completed through a winding 0 of the operators induction coil Z,

the said winding being connected at itsvother terminal to the ground pole of battery. Cur-. rout flowing over this circuit including the winding 0 will induce a like tone current in the coil, which winding is connected through-- the resistance coil 3 across theterminals of inding 0. of the operators induction the operators receiver T, Tone current will therefore be caused to-flow over the opera- :to-1"s;receiver .T rproducing a tone therein 1 which will be heard by the ope 'ator, and in- -:dicate tothis operator that theicall has been answered bysome other operator, in this case by i-theoperator-whose set 18 shown Lint O 'ltxis'appa-rent inzthe system of my inventionanyipractic'al number of operators at- '-'rtempting to answer the same cell after the call has been answered by a first operator, will *be iunsuccessiul in their attempts i and will receive thistone current, the applying of the'tonezcurrent not depending upon any .movable part-s;i11:each of the cord circuits,

butzbein ria 3 lied b a2rela in the first coni e 5 nectedrordcn'cuit will so operate prior to the coimectionof a second cord circuit to a circuit-of the line. In th1s 1way I do away -Wlt-l1' marginal-:ad]us t1nents of the super- .visory (relaysin r the cord circuits.

VVlnle I have illustrated anddescribed the operation of :only two cord circuits,- it will be understood that in practice inmost cases -:each operator will have associated 1th her telephone set a plurality of cord circuits,

-ksuch as illustrated and described.

cl am "aware that other embodiments of .my invention may be'devised for accomplish ng the aforesaid ob ect involving numerousiand'extensive departures from the express disclosure herein attained, but what I l'clainr as my invention is limited only by the scope of the' following claims.

1. In a telephone system,the combination awith a'rtelephonelin eXtended-froni-a substation and :tern'nnatmg at a main station 'inia. luralit "of switchin terminals of a l V e, a

plurality of operators link circuits at the exchange having-answering contacts, each adapted to be connected with aset of'the zsaidswitching terminals, means in a first 112111'16(l'-'Cl161lll) to -associate a source of tone current with interconnected contacts of the saidswitching terminals, means responsive tors of the'said link circuit, and means responsivetothe connection of the said first connected link clrcuit to the switching terminals of the calling telephone line to disable thetone associatlng means of a second connected -link circuit to permit the flow of the said tone current throu 'h the overators setfor the said link circuit, said operators connecting means of the second con- 'to the operation ofthe said tone associating -meansto-cause the connection of the associatedr'operators set to thetalking conducnectedcord circuit being under the control ofthe said disabling means,

2. In a telephone system, the combination with atelephone line leading fron'i a substation to an exchange, of multiple switchboard contacts for the saidline at the exchange, of a plurality ofcord circuits at the exchange adapted to be connected to the" said multiple contacts to answer a call originating at the substation of the said lino, marginal controlling apparatus for each of the said cord circuits, an operators circuit adapted to be associated with ach of the said cord circuits, said operators circuit including a telephone receiver, means including a shunt circuit for the controlling apparatus of a second cord circuit associated with a calling line controlled by the controlling apparatus of a first connected cord circuit to the said telephone line, to prevent the operation of the said second controlling apparatus, and means responsive to the actuation of said controlling apparatus in the first connected cord circuit to apply through contacts of the associated multiple jack of the line a source of tone current to the operators receiver associated with the second connected cord circuit, at the time having its controlling apparatus in an inoperative condition.

3. In a telephone system, the combination with a telephone line extended from a substation and terminating at a main station in a plurality of switching terminals, of a plurality of operators link circuits at the exchange having answering contacts, each adapted to be connected with a set of the said switching terminals, marginal operating means in a first connected link circuit to associate a source of tone current with interconnected contacts of the said switching terminals, said marginal means of a second connected link circuit being normally in operative condition to convey the said tone current to the operators set for the said second connected link circuit, under the control of the said switching terminals and the said answering contacts of both of the said link circuits.

4. In a telephone system, the combination with a telephone line extended from a substation and terminating at a main station in a plurality of switching terminals, of a plurality of operators link circuits at the exchange having answering contacts, each adapted to be connected with a set of the said switching terminals, means in a firstnamed circuit to associate a source of tone current with interconnected contacts of the said switching terminals, the said tone associating means causing the connection of the associated operators set to the talking conductors of the said link circuit, a shunt.

circuit including the tone associating means of the first connected circuit to maintain the corresponding tone associating means operative in a second connected link circuit in its normal operative condition to convey the said tone current to the operators set for the said second. link circuit.

5. In a telephone system, the combination with a telephone line extended from a substation and terminating at a main station in a plurality of switching terminals, of a plurality of operators link circuits at the exchange having answering contacts, each adapted to be connected with a set of the said switching terminals, means in a firstnamed link circuit to associate a source of tone current with interconnected contacts of the said switching terminals, means rcsponsive to the operation of the said tone associating means to cause the connection of the associated operators set to the talking conductors of the said link circuit, and means responsive to the connection of the said first connected link circuit to the switching terminals of the calling telephone line to disable the tone associating means of second connected link circuit to permit the flow of the said tone current through the operators set for the said second link circuit.

6. In a telephone system, the combination with a main station, atelephone line terminating at the main station in a plural.- ity of terminals, a plurality of cord circuits at the main statioman operators set associated with each circuit, means to connect the answering end of each cord circuit to a terminal of the said line, and means responsive to the actuation of the first-named means of a first connected cord to convey a distinctive tone current from the first connected cord circuit to a second connected cord circuit through the said line terminals, the said tone current producing an audible tone in the operators telephone set associated with the second connected cord circuit.

7. In a telephone system, the combination of a main station, a plurality of telephone lines leading to the main station and terminating thereat in a plurality of terminals, a plurality of cord circuits at the main station, each provided with an answering terminal, means to connect each cord circuit through its answering terminals to a line terminal and operators set associated with each cord circuit, means to connect said operators set to the cord circuit, and means to prevent the connection of an operators set to a subsequently connected cord circuit, the first-named operators connecting means controlling the conveying of a tone current from the first cord circuit to the second cord circuit to produce an audible tone in the second operators telephone set.

8. In a telephone system, the combination oi? a main station and a substation, a telephone line for the' said substation terminating at the main station in a plurality of terminals, a plurality of link connecting circuits at the main station, an operators telephone set associated with each link connecting circuit, means responsive to the connection of a link connecting circuit to one of the said terminals to cause the associated operators set to be connected with the said. link circuit, multiple contacts in the said terminals, the said operators set connecting means applying when actuated a fluctuating tone current to the said multiple contacts, and means responsive to the subsequent connection of a second link circuit to a telephone line to convey the said tone current to the second operators telephone set.

9. In a telephone system, the combination with a telephone line extended from a substation and terminating at a main station in a plurality of switching terminals, of a plurality of operators link circuits at the exchange having answering contacts, each adapted to be connected with a set of the said switching terminals, means in a first named circuit to-associate a source of tone current with interconnected contacts of the said switching terminals, means responsive to the operation of the said tone associating means to cause the connection of the asso ciated operators set to the talking conductors of the said link circuit, and means responsive to the connection of the said first connected link circuit to the switching terminals of the calling telephone line to dis able the tone associating means of a second connected link circuit to permit the-flow of the said tone current through the operators set for the said link circuit, said operators connecting means of the second connected cord circuit being under the control of the HARVEY L. HARRIS. 

